The invention generally relates to medical instruments which are suited for grasping objects. More specifically, the invention relates to surgical needle holders.
A needle holder is, for example, known from the firm catalogue “Storz Karl Storz—Endoskope, Volume Laparoscopy, 4. Edition January 2002, Pages NH 1, NH 2 C, NH 3 C, NH4C, NH5C, NH6C, NH7Cand NH8B.
While the present invention will be hereinafter described with respect to a medical instrument for grasping a surgical needle, wherein in such case the instrument is also referred to as a needle holder, the invention is not restricted to such an application and other applications are also conceivable. For example, the medical instrument can be used for grasping an implant, for example a bone screw or a bone nail or the like.
In case of use of a medical instrument mentioned at the outset as a surgical needle holder, a needle can be grasped between the two jaw parts for performing a suturing or ligature operation in the human or animal body.
The needle holders known from the above-mentioned firm catalogue each comprise an elongated shaft, two jaw parts arranged at the distal end at the shaft, and a handle arranged at the proximal end of the shaft. At least one of the jaw parts is pivotable with respect to the other jaw part. The handles of these known instruments comprise two grip parts, one of which is movable and serves as the operating element for moving the pivotable jaw part. Force transmission from the operating element to the pivotable jaw part is accomplished by an axially movable force transmission element, which is configured as a push/pull rod or wire.
In order to facilitate use of the instrument, the known needle holders comprise a latching mechanism for immobilizing the pivotable jaw part in the grasped state, in which the needle must be securely grasped between the jaw parts so as to not drop from the needle holder. The latching mechanism of the known needle holders comprises a ratchet which immobilizes the operating element, i.e. in case of the known needle holders the movable grip part or in case that both grip parts are movable, both grip parts with respect to one another. Other latching mechanisms which are known heretofore comprise an element which engages the force transmission element itself, thus blocking the axial moveability of the force transmission element in the grasped state.
The known medical instruments have the drawback that, besides the degree of freedom of closing and opening the jaw parts, they have no further degrees of freedom or achieve these only with high friction or additional transmission means due to the fact that the latching mechanism of the known medical instruments is arranged in the handle of these instruments and immobilizes the operating element for closing and opening the jaw parts or the force transmission element itself. For example, rotating the jaw parts with respect to the shaft is not possible. For, when the operating element is immobilized, the force transmission element and the jaw part, are also blocked against any further movement with respect to the shaft. A rotation of the jaw parts with respect to the shaft is not possible. Rotation of the jaw parts is only possible by rotating the whole instrument about its longitudinal axis, which is, however, cumbersome.